Winter strawberries possible in North Carolina?

Nestled among the rolling hills of the North Carolina Piedmont Research Station in Rowan County just west of Salisbury are high-tunnel greenhouses that in the dead of winter are teeming with fresh, red strawberries.

The North Carolina State University research project could result in a new winter crop for North Carolina farmers.

The project resulted from a trip to England and Spain several years ago when Jim Ballington, horticultural science professor and small fruit breeder in the North Carolina State College of Agriculture and Life Sciences, saw the use of high tunnels for small fruit production and realized it provided potential for North Carolina.

With a grant from the North Carolina Rural Development Foundation, he teamed with Barclay Poling, also a North Carolina State horticultural science professor and North Carolina Cooperative Extension small fruit specialist, Andy Myers, research operations manager and Joanne Mowery, research specialist, both at the Piedmont Research Station, and Charles Safley, professor of agricultural and resource economics and Cooperative Extension economist at North Carolina State, to explore whether winter strawberry production might be a profitable enterprise for North Carolina farmers.

The high tunnels are 150-foot-long, greenhouse-like structures with rounded tops covered with polyethylene plastic. For the past three years, the research team has studied cultural requirements such as which strawberry varieties grow best, ideal planting dates and how best to provide winter freeze protection.

Researchers have also looked at profit potential and how much yield is possible from late October through mid-April.

After a recent dip in temperatures to 5 degrees F., the plants continued to thrive. "The Salisbury location in the central part of the state seemed the ideal location," said Ballington. "We can't go year-round in any one location in the state to produce strawberries, but we do have the potential to produce strawberries somewhere in the state at least 10 months of the year. This has worked better than we expected and has the potential to put North Carolina farmers in a more competitive position to increase strawberry production."

Strawberry Festival, a Florida strawberry variety, turned out to be the favored variety in the high tunnels due to its consistent production of high quality fruit, said Poling. "This variety with its plump, beautiful fruit and 6- to 8-inch stem makes it popular for stem berry packs, which get the best price in the strawberry market." Improving the productivity and nutritional quality of the berries will be among the next steps the research team will undertake. To strengthen these aspects of the work, they've enlisted Jeremy Pattison, one of the new faculty members with the North Carolina State University Plants for Human Health Institute at the new North Carolina Research Campus in Kannapolis.

"The research team at Salisbury has shown that high-tunnel winter strawberry production in the North Carolina Piedmont is a reality," said Pattison. "However, this system has its challenges — short day lengths and extreme fluctuating temperatures — and we are starting to re-examine how the strawberry plant grows and allocates energy to various plant parts in order to increase production."

The team is also determining how to move the research into real-world application by assisting local farmers in establishing high-tunnel operations. "High tunnel production systems can offer growers an alternative growing system and consequently a new marketing alternative," said Safley, the economist. "However, these production systems can be expensive. The results of this study will serve as a guide to assist growers who are either considering high-tunnel strawberry production or those who are currently growing strawberries in high tunnels to make more informed business management decisions."

Myers, with the Piedmont Research Station, said, "It is very exciting to be working on a project that could lead to a new industry for North Carolina. The Piedmont Research Station is proud to be working with such a talented team of professionals."